Deodorant liquid compositions have become part of many people's personal care and grooming regimen. These compositions may be delivered to the body via a variety of devices such as aerosol sprays, pump sprays, and liquid applicators such as roll-on devices. Such forms of liquid deodorants are described, for example, in U.S. Pat. No. 4,906,454, Melanson et. al., issued Mar. 6, 1990.
The formulation of deodorant products is a delicate balancing of perfume, deodorant active, cosmetic factors and skin irritation factors. The resulting product is often a consumer acceptable product but not an outstanding product in all areas.
Historically, perfumes were used to mask body odors. Today, deodorant compositions not only comprise perfumes, but, also, antimicrobials, herein referred to as deodorant actives. The deodorant actives enhance the ability of the perfumes to mask malodors by destroying the microbes which abide on the skin. The microbes attack sweat gland secretions thus causing the formation of malodorous fatty acids. It is through the combined efforts of the perfume and the actives that deodorants are effective. Unfortunately, this effectiveness is diminished when over the shelf life of a liquid deodorant product the volatile ingredients, such as ethanol, degrade the actives into malodorous subcomponents. Particularly, it has been discovered that a highly preferred deodorant active, zinc phenolsulfonate, degrades into malodorous ethoxyphenols in the presence of monohydric alcohols, e.g., ethanol. Thus the shelf life of liquid deodorants comprising zinc phenolsulfonate and monohydric alcohols is greatly diminished. It is one object of this invention to discover a means for preventing degradation of zinc phenolsulfonate in the presence of monohydric alcohols and thereby provide long lasting odor stability and effective deodorancy in a liquid deodorant composition.
Perceived cosmetics can be important to consumers in a liquid deodorant composition, as can odor stability. Aerosol deodorants have gained wide consumer acceptance due to their excellent cosmetic characteristics.
Aerosol deodorants are typically about 20% to 40% propellant, about 50-70% the volatile monohydric alcohol ethanol, and about 5-10% propylene glycol, a deodorant active and fragrance. Typically, only about 20% to 60% of the sprayable contents actually reach the skin since the liquified hydrocarbon propellant vaporizes as it is sprayed. Many consumers perceive aerosol deodorants as being dryer than conventional pump spray liquid deodorants wherein a very high proportion of the liquid deodorant is delivered to the skin. Deodorant aerosol products usually maintain very good cosmetic acceptance relative to conventional deodorant pump spray products.
Formulating a liquid deodorant composition suitable for application to the skin by a conventional pump spray device and having excellent cosmetics which additionally are comparable to an aerosol-delivered composition is difficult. The use of monohydric alcohols can lead to a cold feel upon application and stinging when applied to an open wound. The use of water can lead to a sticky, wet skin feel. These effects may typically be minimized by the incorporation of emollients, such as volatile and non-volatile silicones, to aid in reducing tackiness and provide a lasting dry feel to the skin. Such emollients, however, can be difficult to formulate into a physically stable liquid deodorant composition. It is a second objective of this invention to provide a liquid deodorant composition suitable for pump spray application which can provide excellent cosmetics which additionally are comparable to those of an aerosol deodorant, and which can exhibit excellent physical product stability.
While balancing the formulation of a liquid deodorant composition to achieve good overall cosmetics and excellent odor stability, one must consider the degree of skin irritation which will be caused by application of the composition to the skin general, many people find the volatile carrier ingredients, e.g., ethanol, to be irritating to the skin especially when applied to an open wound. It is known in the art that surfactant systems are generally harsh to the skin. The use in liquid deodorant compositions of certain polyhydric alcohols, such as dipropylene glycol, in combination with polypropylene glycol (PPG) ethers of C.sub.4 -C.sub.22 fatty alcohols and acids, such as PPG-3 myristyl ether, were found to be irritating to the skin, i.e., cause redness/rash. It is another objective of this invention to provide a liquid deodorant composition suitable for pump spray application which exhibits low skin irritation.
Generally, in the formulation of liquid deodorants useful for pump spray applications, it has been attempted in the industry to solve each of the problems associated with deodorant active stability, cosmetics and skin irritation. These attempts generally have resulted in an improvement, in one or two areas, at the expense of the others or have otherwise provided limited overall improvement. According to the present invention, long lasting odor stability, excellent cosmetics comparable to aerosols, and low skin irritation can be achieved in a stable liquid deodorant composition suitable for delivery in a pump spray device. Furthermore, the deodorant compositions of the present invention still can provide excellent realodor control and overall deodorant performance.